Here’s some rarely seen images from when they were filming the scene where the Jawas carry R2 to the Sandcrawler. I’m pretty sure this was all just for one shot, the one with the matte painting of the crawler. Apparently this was filmed fairly last-minute in the film’s production, in Death Valley CA rather than Tunisia.
Some more info: https://www.reviewjournal.com/news/nation-and-world/little-aliens-in-death-valley-yes-the-proofs-in-the-original-star-wars/